Heffernan provides a brief history of how 'mindfulness' became the English translation of the Pali word sati:

‘It looks like nothing more than the noun form of “mindful” — the proper attitude toward the London subway’s gaps — but “mindfulness” has more exotic origins. In the late 19th century, the heyday of both the British Empire and Victorian Orientalism, a British magistrate in Galle, Ceylon (now Sri Lanka), with the formidable name of Thomas William Rhys Davids, found himself charged with adjudicating Buddhist ecclesiastical disputes. He set out to learn Pali, a Middle Indo-Aryan tongue and the liturgical language of Theravada, an early branch of Buddhism. In 1881, he thus pulled out “mindfulness” — a synonym for “attention” from 1530 — as an approximate translation of the Buddhist concept of sati.

The translation was indeed rough. Sati, which Buddhists consider the first of seven factors of enlightenment, means, more nearly, “memory of the present,” which didn’t track in tense-preoccupied English. “Mindfulness” stuck — but may have saddled the subtle sati with false-note connotations of Victorian caution, or even obedience. (“Mind your manners!”)’

The article continues to describe the history of the word, how it was pulled out of Buddhist religious practice and into secular meditative practice by Jon Kabbat-Zinn, and how it was then commercialized and turned into a kind of self-help rorschach word.

She suggests the (perhaps necessary) inexactness of Rhys Davids' original translation enabled that development. If sati had really been translated exactly to something as koanic as "memory of the present", it wouldn't have so easily slipped into the world of self-help, whereas a word like "mindfulness" means almost nothing, and so it can be made to mean almost anything. And it sounds great, to boot.

It's fascinating to consider how the choice of translation of a single word could lead to a deluge of self-help, and the article's worthwhile for that alone, but it also contains refreshing skepticism about all of mindfulness today. If you're meditating or thinking of starting, and if you find yourself listening to a lot of wild claims, you might want like to keep in mind Heffernan's closing thought:

‘And that's what commercial mindfulness may have lost from the most rigorous Buddhist tenets it replaced: the implication that suffering cannot be escaped but must be faced. Of that shift in meaning—in the Westernization of sati—we should be especially mindful.’

(Note that here the word "suffering" is used in the Buddhist sense. It doesn't have an easily quotable meaning. Of its several common meanings, the one that sticks out to me as very tangible and clearly understood is—and here I'll just quote Wikipedia—‘The anxiety or stress of trying to hold on to things that are constantly changing.’ I've been guilty of this holding on, but that, I think, is for another post.)